Monday’s presentation of oral arguments before the Supreme Court of the United States (SCOTUS) in the “Christie II” sports-betting legalization case between the US state of New Jersey and the US’s major sports organizations marks the beginning of the final stage in this years-long battle.

At stake is whether the US’s broadly framed Professional and Amateur Sports Protection Act (PASPA) will remain in force, continuing a quarter-century-long federal ban on single-event sports betting in all US states except Nevada. Should PASPA be declared to violate the US’s anti-commandeering laws (which prevent the federal government from taking control of issues already ceded to individual states.

Such a nullification of PASPA, should its basis be declared unconstitutional, would likely bring legalized sports betting to several states across the US. New Jersey would lead the way, with casinos and pari-mutuel facilities there likely opening up in-house books within days or weeks, but several other states already have pending legalization efforts on deck should New Jersey prevail.

Some months down the road, when the nine-justice court hands down its decision, we’ll have the answer. The decision by the nine justices is absolute.

Monday’s hearing, the first of several high-profile cases with oral arguments before SCOTUS scheduled this week, drew a healthy crowd of attending media and even generated mainstream headlines later in the day. Pro-gambling pundits in attendance were exuberant in noting that most of the questions were directed at the attorneys representing the five prominent sports organizations — the NFL, NHL, MLB, NBA and NCAA — in the process exposing several hypocritical claims.

Among the most exuberant claims, albeit before the actual hearing of arguments, was that New Jersey might prevail on a unanimous, 9-0 count. That’s highly unlikely; far more probable is that this will be a close decision, either a 5-4 or 6-3 decision in favor of either New Jersey or the sports organizations and PASPA.

It’s important to remember that New Jersey narrowly lost at both appellate stops before succeeding, against the odds, in having the matter heard by SCOTUS. This suggests that another close, narrow ruling is likely to occur.

There’s also the matter of PASPA being existing law, which appellate judges are historically reticent to override. At least two factors mitigate that, however. First, this is the first federal-level challenge to PASPA’s constitutionality in its 25-year history, making it a “new” matter for SCOTUS consideration. Second, legal scholars have struggled to find a parallel construct in other federal laws to compare against PASPA’s a priori restraint against the states, meaning that PASPA’s defenders (the lawyers for the sports leagues) didn’t have much for existing case law to use in their arguments in the case.

DC-based SCOTUS reporter Chris Geidner’s takes on the hearing were typical. Wrote Geidner, via Twitter, “First take: The justices (at least a majority) were uncomfortable with a federal law that goes out of its way to say what a state can’t do, while setting up no regulatory system of its own. #SCOTUS.”

Geidner also suggested that the line of questioning taken by at least five of the nine SCOTUS justices suggested they were hesitant to believe PASPA’s commandeering approach was valid.

One pro-gaming attorney in attendance, Christopher Soriano of Duane Morris LLP, suggested that SCOTUS justices John Roberts, Anthony Kennedy, Samuel Alito, Neil Gorsuch, and Stephen Breyer, were probable votes in favor of New Jersey, with a possible sixth vote coming from venerable SCOTUS justice Clarence Thomas.

We’ll see. Unfortunately, such prognistications have proven too optimistic in the past, though this is the all-or-nothing shot. Should New Jersey prevail, the state-level gates are effectively open. Should the leagues win again, then it’s back to the drawing board, with PASPA still the (unpopular) law of the land for several more years.